Can send email but not recieve from a second domain-- first domain works perfect

Ok basically i said it all in the title. My first domain works fine as far as sending and recieving email goes, but when i add an email account on the second domain it sends fine but not recieves.... I am miffed at the moment. heres the email failure. It reaches my server but the server doesnt recognize the email address???

The original message was received at Mon, 30 Jul 2007 00:04:14 -0400 (EDT)
from root@localhost

*** ATTENTION ***

Your e-mail is being returned to you because there was a problem with its
delivery. The address which was undeliverable is listed in the section
labeled: "----- The following addresses had permanent fatal errors -----".

The reason your mail is being returned to you is listed in the section
labeled: "----- Transcript of Session Follows -----".

The line beginning with "<<<" describes the specific reason your e-mail could
not be delivered. The next line contains a second error message which is a
general translation for other e-mail servers.

Please direct further questions regarding this message to the e-mail
administrator or Postmaster at that destination.